Recently, network systems have been proposed in which, for example, household electric appliances are connected via a local area network (LAN) to each other (refer to, for instance, JP-A-2002-319947).
Also, other network systems have been proposed: air conditioners, electric lamps, and the like are controlled by a compact remote controller; washing machines are proposed, the optimum washing course of which can be downloaded through the Internet; and refrigerators in which if a stock of beers is decreased, then beer orders are automatically issued (refer to, for example, “JEITA releases model house where 50 sorts of network household electric appliances are installed” by C.HORIKIRI, [online], Tech-On!, [retrieved on Oct. 25, 2005], Internet    <URL:http://techon.nikkeibp.co.jp/members/01db/200201/1006 405/>)